1. Field of the Invention
This invention pertains generally to the field of cutting. More particularly, the present invention pertains to processes of cutting during movement of the work and a flying cutter, and also to apparatus having multiple flying cutters, including multiple types of flying cutters.
2. Description of the Related Art
In modern manufacturing, there have been many high speed processes designed for many diverse industries that rely upon a continuous feed of source materials and which act upon those source materials to produce a resultant work product. These processes use machinery to automatically operate upon the source material at high speed. The throughput, or volume of product per unit of time, determines the added cost per individual product produced, since the fixed cost of a machine and the hourly labor rate for one or more machine operators is divided amongst the numbers of products produced. To better appreciate this, presume two machines cost the same to purchase and require the same amount of labor to operate. If one machine can produce 10 times the parts per hour that the other can, the higher production machine only adds one-tenth as much cost per part. This makes parts produced using the higher speed machine far less expensive, giving the owner substantial competitive advantage. As can be appreciated then, production costs and efficiencies are often determined in a large part by the throughput of the machine.
Throughput of a machine and the human labor required to operate the machine are controlled by a number of diverse and quite complex factors. One of these is the percentage of time the machine is operational. Several factors directly and significantly affect this operational percentage, including how reliable the machine is, and whether the machine can be continuously provided with all necessary source materials.
It is apparent that if the machine breaks down frequently, and requires substantial time consuming repairs to get it running again, the operational percentage is poor. In contrast, the adage “like a well-oiled machine” simply refers to a machine that just keeps running, requiring only nominal maintenance. In a well-designed machine, the maintenance required is minimal, and where ever possible is provided during the operation of the machine. Most preferably, any further maintenance may be conducted at pre-planned times or intervals between production runs, rather than after a breakdown in the middle of a production run. This may be likened to the maintenance of an aircraft. Most preferably, all necessary maintenance of an aircraft occurs between flights. The same is true for a production machine. If the machine breaks down, any in-process material may have to be manually extracted from the machine and sold or recycled as scrap or waste, further increasing labor and materials cost without producing any useful product.
Another factor that affects machine reliability for a given machine cost is the way the components of the machine are operated. When parts run in a discontinuous manner, with very fast starting and stopping, this produces large and undesirable forces within the machine. Over time, these forces will either lead to material fatigue or excessive wear. Both result in early parts failure, which in turn requires either more machine maintenance, meaning more frequent down time and less machine productivity. To avoid this extra down time, a machine may instead be built with much more expensive machine parts, either of larger and heavier build, or where that is not possible, very expensive specialty materials. Larger and heavier parts further increase inertial and frictional forces, so the parts need to be even further enlarged. As may be appreciated then, a design that requires unnecessary fast starting and stopping will in turn either need to be fabricated from much more expensive components, or it will break down frequently. This extra cost is a direct result of the operation of the machine, which is discontinuous rather than continuous.
The continuous availability of source materials is also very important to keep a machine running. Wherever possible, the source material is preferably produced in a continuous manner and then fed directly into the machine for processing. One very popular and low cost fabrication method where this is achieved is the extrusion of product. Extrusion processes are often applied to the fabrication of materials that may be melted or softened with heat. The materials are then pumped or pressed through a shaping die, and cooled sufficiently after shaping to be further processed. It will be apparent that if the extrusion press is run continuously, there will be a nearly indefinite length product produced. Examples of a few products produced using an extrusion machine are tubing, wire, rod, and sheet goods, and also various plastic and metal channels such as trim, window and door frames, and many, many other diverse products. The product may then be spooled for later use or further fabrication, or it may be immediately processed further.
In some industries, source materials are not reasonably produced simultaneously with later operations, and so in many of these cases, the source material may be provided in a large roll upon a spool or the like. Printing is but one example, where the paper fabrication is normally performed at a paper mill physically distinct from the high speed printing presses that convert the paper into magazines, newsprint, and other diverse products. In such cases, the spool will preferably be sufficiently large to be used for a relatively long period, allowing a very large quantity of finished product to be produced in a single continuous run. This may also apply to some lower volume products, where the cost of an extrusion machine may not be justified and instead the product may be supplied from a spool.
Whether from a large spool, or from a continuous extrusion process, a machine will preferably be provided with a relatively long run. However, finished product is nearly always much smaller or shorter than the roll or spool of stock material, or some segment of the extrusion, necessitating use of a cut-off apparatus to cut the stock into manageable or useful lengths. In addition, depending upon the product being produced, other operations may need to be carried out discontinuously along the length of the material. Common operations include notching or other shaping in a direction offset from the length or longitudinal axis of the extrusion or spooled stock material. Most preferably, all of these additional operations will be performed on the parts prior to cutting. Otherwise, there would need to be additional apparatus to collect the already-cut material, handling to move the cut material to a second machine, feeding equipment to move the cut material into the second machine, and the additional processing equipment. If, instead, the existing machine may be relatively simply fit with extra tools to complete these additional processes, such as notching or shaping, this alleviates the problems and expense associated with the second machine.
To perform the cutting and additional forming operations, a cutoff apparatus having a cutting tool and possibly other tools that moves in synchronization with a workpiece or stock material is commonly used. These tools are commonly referred to as flying tools, since they move at very high speed preferably at first in synchronization with the workpiece and then opposite thereto to reposition for the next operation. Typically, the tool is mounted on a carriage which in turn is slidably supported on a base for movement in a direction generally parallel with the workpiece's path of travel. The carriage accelerates from a stationary starting position along the path of travel of the workpiece until the rate of travel of the carriage equals that of the workpiece itself. Depending upon the type of workpiece involved, a clamp may be provided on the carriage for clamping the workpiece to the carriage, to assure that the workpiece is held stationary relative to the carriage prior to the cutting operation. The cutting tool is then accelerated to complete the cut, and decelerated or reversed to prepare for the next cut. After the workpiece is cut and otherwise operated upon, the carriage decelerates and returns to its starting position, in preparation for the next operation. To move the carriage and tools at this high rate of speed, hydraulic and pneumatic cylinders are frequently used. The cylinders are commonly double acting, meaning that a forward actuation extends the output shaft to accelerate the carriage to the speed of the workpiece, while reverse actuation of the cylinder retracts the output shaft, returning the carriage to its starting position. Unfortunately, precise control over these cylinders is not practical, meaning the cylinders are simply driven as quickly as possible to an extreme of travel, and then either immediately stopped or fully reversed therefrom. Control is commonly achieved using simple valves that either abruptly allow the flow of fluid to the cylinder, or that equally as abruptly cut-off flow thereto. As a result, there is a substantial amount of noise or “racket” created by these machines, as the valves open and close and the machine parts are slammed to and fro. This can at first blush appear to be very productive, a person tending to believe that the hammering sounds equate to improved speeds and productivity. However, as aforementioned, this high force acceleration of machine parts is in fact undesirable, and will necessitate either greater down time or greater cost for parts used within the machine.
Another issue relating to the cost of a production machine is the flexibility afforded by the machine. In other words, if the machine is not adaptable, it can only be used to produce a single part or type of part and will be idle when there is no demand for that part. However, an adaptable machine that can be used to produce a wide variety of parts may be operated on a nearly continuous basis, only being shut down for brief periods of simultaneous maintenance and minor tool changes.
A number of patents illustrate various flying notching and/or shearing equipment that are representative of the art. These exemplary patents and others which are provided herewith, the contents and teachings which are incorporated herein by reference, include: U.S. Pat. Nos. 3,211,037 by Lucien, entitled “Flying cutter with camway controlled actuating means”; 3,656,385 by Kimbrell, entitled “Apparatus for machine forming extruded plastic siding”; 3,670,609 by Contaldo et al, entitled “Method and apparatus for controlling shearing of metallic workpieces”; 3,704,643 by Cookson, entitled “Flying Shear”; 3,717,058 by McMinn, entitled “Flying Cut-off Press”; 3,732,741 by Defontenay et al, entitled “Devices for controlling the carriage of a portable shear”; 3,998,119 by Schroter, entitled “Process and apparatus for punching sheets or webs of paper, cardboard or similar material”; 4,179,962 by Crump, entitled “Combined flying cutoff and punch”; 4,191,078 by Steinhilber, entitled “Wire cutting flying shear”; 5,195,412 by Flemming et al, entitled “Notching and shearing machine for exterior siding panels and method of using same”; 5,224,368 by Schach, entitled “Flying die machine”; 5,361,662 by Levy entitled “Moving hydraulic press”; and 5,383,381 by Graham, entitled “Double cut die set”. Several additional cam operated machines, the contents and teachings which are incorporated herein by reference, include 3,680,616 by Rejsa, entitled “Method and apparatus for severing food products”; 3,972,299 by Hasselbeck et al, entitled “Can body trimmer”; and 4,354,409 by Riera et al, entitled “Flying cutoff machine”.
Finally, other US patents for which the contents and teachings are incorporated by reference include U.S. Pat. Nos. 392,362 by Ridley, entitled “Combined punching and shearing machine”; 2,992,581 by Friesz, entitled “Web cutting and notching device”; and 5,724,246 by Heil, entitled “Arrangement for the controlled notching and cutting of framing components”.
Webster's New Universal Unabridged Dictionary, Second Edition copyright 1983, is additionally incorporated herein by reference in entirety for the definitions of words and terms used herein.